From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AFC2FC433EF for ; Sat, 9 Apr 2022 08:16:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237426AbiDIIS6 (ORCPT ); Sat, 9 Apr 2022 04:18:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230349AbiDIIS4 (ORCPT ); Sat, 9 Apr 2022 04:18:56 -0400 Received: from mail-wm1-x32a.google.com (mail-wm1-x32a.google.com [IPv6:2a00:1450:4864:20::32a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47AA023E3DD for ; Sat, 9 Apr 2022 01:16:49 -0700 (PDT) Received: by mail-wm1-x32a.google.com with SMTP id r64so6903687wmr.4 for ; Sat, 09 Apr 2022 01:16:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=philpotter-co-uk.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Nnj60HFFj8COyd309Q8C6JWWM2qlsDx/H5COLD9jni8=; b=Jkup3xP4Pyeoph/uPUgtPXmFRMFfrlm5hI8M1PLvow7rEF2jlyzt31uNDEv/+dW+JO rYSLpq2Yog1QOGQgoAygrbvXj6sFx++pyhAQvHDAMKshdH7iIT0fuvN6kY3gUn8o0AwN z3obSLhRnQgHu/WM1G3Wp2H23hJcuhD6QosMEYsZjhLlGOgsi/M1RCPmDiq4zuUOdGnw cGkIxbFPA1YdoOLzMch9UleiQEefQMk+D0Vi/DUf4NlzSwuE+fMbFL3ySroCUfsvgB9Z u6WbS+25xCl9JGJKG8/bZbO3qVAiZsPL2FQlmM3ylaQ/5ohVAA9AbNeujap5pYW7pT3z j+Iw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Nnj60HFFj8COyd309Q8C6JWWM2qlsDx/H5COLD9jni8=; b=iqaUJxiRk/bmPuIFCUCPeW03Fs4Wp6dVgXHq8HaLQMlE7GGOfWVW6MX0XBN/OehgaZ B3OBq2HpxPQQUsl6m3dVNhRgZJNqttiw+gdwzmkWDO6P6ddKoVvw67u1LfWyLkLSg9oY K8h8VhM4tLYh4Y87tohFXTGOkt2uPDhjrwUbn3FTxGbaHugnLm6zRVJqs9pdXPpHc4vX 6Bjp3PEtYctD4vgF1O2YP4Gn1b7TTzAg6U9V+3RZw4iwwNADTJNNiAaVma8YT3jfjrE4 2CapoR/hjHzsBJDEDp1y9jjB8K+XLQEB/j4Ml2QWr48LHRL/fT0/IILj5rwXOjlLVguJ CruA== X-Gm-Message-State: AOAM530exQx3r5OlUuMQOXbZZmz4Hy87A8DQBXGB1UDPJYRNRN6v4vjC Leanrn8MD+Tz67p5YJmQmsXjxw== X-Google-Smtp-Source: ABdhPJyeRD2BNsre1rwgXFtmHQTdGvTWlL1y11A1d0Mq4HeSv3wo5ybni3Rj4482qnw1KVHVUVztbg== X-Received: by 2002:a05:600c:384e:b0:38c:9a8a:d205 with SMTP id s14-20020a05600c384e00b0038c9a8ad205mr19829564wmr.44.1649492207835; Sat, 09 Apr 2022 01:16:47 -0700 (PDT) Received: from equinox (2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.a.1.e.e.d.f.d.0.b.8.0.1.0.0.2.ip6.arpa. [2001:8b0:dfde:e1a0::2]) by smtp.gmail.com with ESMTPSA id 185-20020a1c19c2000000b0038a1d06e862sm12440449wmz.14.2022.04.09.01.16.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 09 Apr 2022 01:16:47 -0700 (PDT) Date: Sat, 9 Apr 2022 09:16:45 +0100 From: Phillip Potter To: Enze Li Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Subject: Re: [PATCH] cdrom: do not print info list when there is no cdrom device Message-ID: References: <20220408084221.1681592-1-lienze@kylinos.cn> <25390602-cfa0-dba3-bfbc-a35ed6b44bcf@kernel.dk> <20220409122530.60353fcd@asus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220409122530.60353fcd@asus> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 09, 2022 at 12:25:30PM +0800, Enze Li wrote: > On Fri, 8 Apr 2022 06:34:04 -0600 > Jens Axboe wrote: > > > On 4/8/22 2:42 AM, Enze Li wrote: > > > There is no need to print a list of cdrom entries with blank info > > > when no cdrom device exists. With this patch applied, we get: > > > > > > ================================================ > > > $ cat /proc/sys/dev/cdrom/info > > > CD-ROM information, Id:cdrom.c 3.20 2003/12/17 > > > > > > No device found. > > > > > > ================================================ > > Hi Jens, > > Thanks for your review. > > > > > And what did we get before? > > Without the patch, we get: > > ================================================ > $ cat /proc/sys/dev/cdrom/info > CD-ROM information, Id: cdrom.c 3.20 2003/12/17 > > drive name: > drive speed: > drive # of slots: > Can close tray: > Can open tray: > Can lock tray: > Can change speed: > Can select disk: > Can read multisession: > Can read MCN: > Reports media changed: > Can play audio: > Can write CD-R: > Can write CD-RW: > Can read DVD: > Can write DVD-R: > Can write DVD-RAM: > Can read MRW: > Can write MRW: > Can write RAM: > > > ================================================ > > > > > Will this potentially break applications that parse it? > > > > I dunno, is there any way to confirm this thing? And if this is really > a possibility, does it mean that we cannot make changes? > Sorry, anything that can be parsed from userspace has the potential to break userspace applications. For that reason, I would have to say I don't think this patch is suitable. Sure there are times it's appropriate to change userspace interfaces, but I'd rather err on the side of caution here. Thanks for the patch though. Nacked-by: Phillip Potter Regards, Phil